1. Field of the Invention
The present invention relates to an unfoldable connected structure and a method for unfolding such structure for constructing a large space structure by unfolding the structure in aerospace.
2. Description of Prior Art
In the past, in order to construct a large structure such as a space station or a solar battery structure for an electric propulsion spacecraft in the aerospace, works done by astronauts outside a spaceship have been inevitable, or developments for intelligent robots have been desired. However, for manned spacecraft, it is required to train the astronauts for a long time, and there is always a life at risk. As for intelligent robots, there is a problem of high development cost. As a result, recently, developments have been made for methods for constructing large space structures by using unfoldable connected structures which can be transported to aerospace in their folded states and unfolded in aerospace by driving force of a motor.
One example of such unfoldable connected structures is disclosed in Japanese patent un-examined publication (JP Kokai) No. 2001-132893. In this example, the unfoldable connected structure is obtained by connecting twenty structural units of equilateral hexagon to form a spheric shell structure.
However, the unfoldable connected structure described in JP Kokai No. 2001-132893 has twelve pentagonal voids when the twenty structural are connected to form the spheric shell structure. Therefore, it is difficult to improve the structural strength of this unfoldable connected structure.